*
**
The rise in drug resistance coupled with toxic effects of the available antibiotics has brought in focus the alternative of using a synergistic approach to drug therapy thereby countering the problem of inefficacy and toxicity of conventional drugs against resistant microbes. In the present study emodin, a known anti-staphylococcal compound, isolated from Rheum moorcroftianum was found active against vancomycin resistant Staphylococcus aureus and Staphylococcus epidermidis strains. The synergistic effect of emodin in combination with vancomycin was studied through modified cheqerboard dilution method on the growth of MRSA and vancomycin resistant mutant of Staphylococci. The FIC indices revealed all combinations to be either synergistically or partially synergistically active against both the bacterial species. The most synergistic effect was observed in vancomycin resistant mutant of Staphylococcus epidermidis and Staphylococcus aureus strains in which concentration of vancomycin needed to inhibit the strains was reduced from 4.0μg/ml -3.0μg/ml to 0.5μg/ml-0.375μg/ml in the presence of emodin 1.56μg/ml. The combining effect against MRSA was lower (partial synergism) than that against vancomycin resistant mutant of Staphylococci but no antagonism was noticed. In addition to the growth inhibitory potency of emodin against VRSA and MRSA, the synergistic effects with vancomycin make these compounds potent phytotherapeutics agents against, not only VRSA infection, but MRSA infections as well.
